1)
What was the fear?
1.
Rashi: Belshatzar was 'paid' (punished for using Klei ha'Mikdash).
2.
Radak: They will fear (refer to 14:5:2:2).
2)
Why does it say "Ki Elokim b'Dor Tzadik"?
1.
Rashi: This refers to the generation of Yechanyah; they were Tzadikim.
2.
Radak: [They will fear, for they will realize that] Elokim will be with a righteous generation to help them.
3.
Malbim: All sinners know that Elokim [judges] in a generation of Tzadikim, after he does a miracle for Yisrael and saves them. Then they know that Elokim has Hashgachah Pratis over them.
